This invention relates to biodegradable alkylene oxide-lactone copolymers. In one aspect, the invention relates to random copolymers of one or more lactones and one or more alkylene oxides while in another aspect, the invention relates to such copolymers capped with an alkylene oxide block which comprises the same and/or one or more different alkylene oxides as that used to make the copolymer. In another aspect, the invention relates to uncapped random copolymers of one or more lactones and one or more alkylene oxides, the copolymer made with a polyfunctional initiator. In yet another aspect, the invention relates to processes of making the alkylene oxide-lactone copolymers and to using these copolymers as nonionic surfactants and foam control agents.
Polyoxyalkylene block copolymers and homopolymers, also known as polyalkylene oxide block copolymers and homopolymers, are widely used as nonionic surfactants, foam control agents, mineral wetting agents, surfactants for use in cleaning formulations, emulsifiers, de-emulsifiers, dispersants, synthetic lubricants, and any application where surfactancy, lubricity, or foam control is important. In particular, polyoxyalkylene copolymers made from propylene oxide (PO), the butylene oxides, particularly 1,2-butylene oxide (BO), and ethylene oxide (EO) represent a major class of such materials.
In general, the hydrophilic portion of nonionic surfactants and foam control agents is typically a polyoxyethylene (POE) moiety. The hydrophobic block can be derived from a larger set of possible materials, examples of which are alkylated phenols, fatty alcohols and acids, polyoxypropylene (POP), and polyoxybutylene (POB). Each hydrophobe imparts unique performance attributes to the nonionic surfactant or foam control agent of which it is a part.
Polyglycol-type block copolymers typically exhibit a high degree of resistance to biodegradation. In general, however, polyglycols do eventually biodegrade over time, but not during the time period specified in most standardized tests.
Copolymers of alkylene oxides and lactones are known, e.g. U.S. Pat. Nos. 2,962,524, 3,312,753, 3,689,531, and 4,291,155, all of which are incorporated herein in their entirety by reference, but these copolymers are not capped and many are made with monofunctional initiators.